begeman



Sept 6, 1932. H. G. BEGEMAN MUFFLE KILN Filed Aug. 23. 1930 2 Sheets-Sheet 2 Patented Sept. 6, 1932` HENRY G. BEGEMAN, OF NEW YORK, N. Y.

MUFFLE KILN Application led August 23, 1930. Serial No. 477,420.

This invention relates to a continuous tunnel muiiie kiln, used for firing ceramic or other roducts, and especially to a kiln with a mu e closed' at the bottom, requiring no cars for transporting the ware through the kiln, but using refractory or metal slabs as carriers of the ware.

Such continuous muiiles, in which slabs for carrying the ware are being moved over the stationary bottom of the ware have been well known in the art for over 30 years and principally consist of a preheating, high temperature and cooling zone. Heretofore these muiies have been heated either on the bottom,

' sides and top, or on the bottom and sides only.

The bottom had to be the hottest part if approximately uniform temperature was de` sired throughout the muiile. Since the heated bottom is considerably hotter than the hotl 26 air in the muiie, the layer of air touching the bottom will naturally be more highly heated than other layers of air in the muiile, and since the weight of the air will decrease with the increase in temperature, the hotter and lighter bottom layer will rise to the top of the muiie and will be replaced by the colder and heavier layer of air in the inutile, which upon touching the muilie bottom will then be heated up and rise to the top, etc.

This continuous up and downward movement of the air, however, not only moves the air, but practically all the dust contained in the air, which, being heavier than air, would settle on the bottom of the inutile if it was not continuously stirred up by the rising air. This condition is very detrimental to ceramic ware and especially to glazed ware as any dust and grit contained in the air will adhere to the glaze while it is in a sticky condition and burn in with the glaze thereby spoiling the appearance of the ware. l

This great disadvantage will be entirely eliminated by my invention, comprising means for keeping the bottom much colder than sides and top of the muile whenever ware is fired to which dust is detrimental.

This is accomplished by entirely disconnecting the bottom flue from the side flues and by providing the bottom flue with a separate burner. It is obvious that this arrangement will allow to vary the temperature of the muiile bottom within a very wide range. For instance, when firing certain bisque ware, which cannot be spoiled by dust, and which also requires higher temperature than glost tiring, the bottom should preferably be hotter than the sides of the muiiie, but when glost ware is red the burner for the bottom iue would either be suiciently throttled to keep the muHe bottom cool enough or should be entirely shut oli", so that the muiie is heated from the sides only. If the ware requires no bottom heat at any time, the bottom heating flue could be entirely eliminated.

If no heat is applied to the bottom of the muftle it will be advisable to apply more heat to the lower part of the side muHe tiles than to the upper part. This, of course, can be accomplished by separating the side flue into upper and lower Hue and by heating either one by a separate burner or separate set of burners.

My invention, however, does away with this necessity and accomplishes 'the same result with only one burner or one set of them. Burner and flue are so arranged that either all or most of the flame or hot gases from the burner will pass only through the lower part of the flue in such a way that the upper part will either entirely or partly be indirectly heated by the heat of the lower part of the flue and regulating 'means are provided, which make it possible to change the ratio of heat applied to the lower and upper part of the Hue. i

Although I generally do not supply any heat to the top of the mule in the preheating and high temperature zone, I provide cooling dues inthe cooling zone of the kiln either all around the mulle or on both sides and top of the muile in such a way that no fan is required for pushing or pulling the cooling air through the flues, but that suiiicient cooling air can be applied to the muiiie tiles by the natural draft of a hot air stack in such a way, that different sections of the cooling end of the muttle can be regulated separately.

Heretofore the only means for regulating the preheating curve of the ware consisted in drawing the waste gases olf at several pairs of ports. I have improved the preheating curve considerably by providing inletsfor cold air at intervals in the waste gas lue in such a way that these cold air inlets can be regulated to suit the desired curves.

In the accompanying drawings, showing certain preferred embodiments of the inven- Fig. 1is a longitudinal horizontal section of the tunnel muflie kiln along line 1 1 of Fig. 2.

Fig. 2 is a longitudinal Vertical section along line 2 2 of Fig. 1.

Fig. 3 is a longitudinal vertical section along line 3 3 of Fig. 1.

Fig. 4 is a cross section along line 4 4 of Fig. 2.

Fig. 5 is a cross section along line 5 5 of Fig. 2, and y Fig. 6 is a cross section along line 6 6 of Fig. 2.

rIhe entire structure is built up of masonry, So as to form a muille chamber 1 through which travel slabs 2, running on balls 3 over the muflie bottom 4 which separates the muilie from the bottom flue 5. Tiles 6, forming the sides of the muiile, separate it from heating lues 7 and cooling flues 8. These cooling lues lead to the top flue 9 and hot air stack 10. The bottom heating flue 5 connects with side lues 7 through ducts 11 and the waste gases travel from side ilues 7 through ducts 12 into the chimney 13. Tiles 14 separate the iiues 7 into lower and upper' compartments, connected by passages 15. Dampers 16 regulate the volume oi' waste gases passing through the upper compartment. Heat is supplied to the flues 7 by'burners 17 and to flue 5 by burner 18. In case of coal iiring etc. these burners can be replaced by iireboXes. 19 indicatesan opening which may be used for closing some of the passages 15 by lirebricks. 2O are cold air inlets for regulating the preheating curve, the amount of air to be regula-ted by slides 21. The cooling air enters at openings 22, which can be regulated by slides or other means 23. The ware 24 is placed on suitable supports 25, resting on the movable slabs 2. 26 is the charging end and 27 the discharging end of the muiile.

In operating the kiln, the loaded slabs enter the muiie at' 26 and are slowly moved through the preheating, burning and cooling zone towards the discharge end 27. The movement of the slabs can be either intermittent by pushing 1 slab length at a time, or continuous by a suitable pusher (not shown) located at the charging end of the kiln. The speed of pushing depends on the ware and temperature. The ware is ready for handling when leaving the kiln.

While I have described the best forms of my invention now known to me, it will be apparent to those skilled in the art, that many changes may be made without depart# ing from the spirit of my invention.

I claim as my invention:

1. In a continuous tunnel mulle kiln separate heating lues for the bottom and each side ofthe mule.

2. In a continuous tunnel mutlie kiln separate means for heating the bottom and each side of the mulie.

3. In a continuous tunnel muille means for regulating the temperature of the bottom heating flue independentlyof the side heating iiues.

4. In a continuous tunnel mule kiln means for regulating the temperature of the bottom heating flue and of each side iiue independently.

5. In a continuous tunnel muiile kiln means Jfor heating the mule on the sides only and for regulating the temperature of each side separately.

6.. In a continuous tunnel mutlie kiln, having movable slabs for carrying the ware sliding over the stationary bottom of the muffle, means for heating this bottom independently of the sides.

7. A continuous tunnel Inutile kiln having side heating iiues divided into lower and upper compartments and means for heating these compartments from the same burner or iireboX.

8. A continuous tunnel mutlle kiln with s1de heating iues separated by spaced tiles into lower and upper compartments, having one or more dampers in the upper compartment adapted to be regulated, whereby either all gases pass through the lower compartment, heating the upper compartment by radiatlon only, or else part of the gases also 'liow through. the upper compartment simultaneously with the gases in the lower compartment and in the same direction.

9. In a continuous tunnel muffle kiln separate adjustable air inlets for each cooling compartment under the mutlie and at the sides of the mulle.

In testimony whereof I aiiix my siXn ature.

HENRY G. BEGEMAN.

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